Cyberduck, a robust FTP/FTP/TLS/SFTP browser on the Mac, is simple to use thanks to its lack of visual clutter and intuitive features. Spotlight, Bonjour and Keychain are all supported.
The software is free but it is donationware. To support development, please consider a $10 donation.
Cyberduck is an Open Source product that is licensed under the GPL. It is free to use. To help develop the future, donations are welcome. Cyberduck is now available in English, Japanese and Catalan, Chinese (Traditional & Simplified), Czech and Danish, Finnish, French and Hungarian.